1. Field of Invention
This invention relates to an electrical contact for connection to a mating connector.
2. Related Art
An electrical contact is used at a region where it is connected to a terminal of a mating connector, and specifically such an electrical contact is used within a connector, various kinds of connection boxes and so on.
There are occasions when such electrical contacts are used in an environment (for example, in a transportation vehicle such as an automobile) in which vibrations are applied to these electrical contacts. In this case, an electrical contact point portion of the electrical contact, contacted with a mating connector, slightly (finely) slides, and this results in a problem that the contact point is worn, so that the electric resistance of the contact point increases.
This will be described with reference to FIG. 7. FIG. 7 shows a connector terminal y having an electrical contact portion 30 (shown in cross-section). An extension portion extends from a front end (facing in a direction of connection with a mating connector) of a bottom portion of a box-shaped portion 31, and is bent to form a spring portion 32a at a front end portion of the box-shaped portion and also to form a contact piece portion 32 disposed within the box-shaped portion 31. A contact point portion 32b of the contact piece portion 32 is adapted to contact a contact piece portion (not shown) of the mating connector to be electrically connected thereto. An upper contact piece portion 33 is provided at a top wall of the box-shaped portion 31, and is adapted to contact a contact piece portion (not shown) of the mating connector to be electrically connected thereto.
When the terminal xcex3 is subjected to vibrations, the vibration of the box-shaped portion causes a fine sliding movement between the contact piece portion 33 and the contact piece portion of the mating connector. As a result, the contact piece portion of the mating connector vibrates, so that a fine sliding movement also develops between the contact point 32b of the contact piece portion 32 and the contact piece portion of the mating connector. As a result of wear of these contact points, the electric resistance increases.
There have been proposed electric connectors which prevent wear due to such fine sliding movement.
One such example is a connector terminal xcex4 shown in FIG. 8.
The connector terminal xcex4 comprises two parts, that is, a box-shaped portion xcex41, and a body portion having contact piece portions 40 and a wire connection portion 41. The two portions are integrally connected together through fixing portions 42 and press-clamping portions 43 by pressing. With this integral construction, vibrations, applied from the exterior, are absorbed by spring portions 44, and therefore are hardly transmitted to the contact piece portions 40, so that a fine sliding movement between the contact piece portions 40 and a contact piece portion of a mating connector is prevented. However, this structure comprises the two parts, and besides there is required an apparatus or the like for assembling these parts together, and therefore the production cost is extremely high.
FIG. 9 is a cross-sectional view of a connector terminal xcex5 proposed in Japanese Patent Unexamined Publication No. 10-189102.
This terminal is received in a terminal receiving chamber in a connector housing so as to provide an electric connector. This terminal includes an electrical contact portion 50 for connection to a terminal (not shown) of a mating connector, and a wire fixing portion 60 for connection to a wire.
This terminal xcex5 is formed by blanking a piece from a flat stock and then by bending it. The appearance of the electrical contact portion 50 is a box-shape, and a resilient contact piece portion 52 is provided within the electrical contact portion 50, and is supported by an interconnecting portion 51 extending from a side wall of the electrical contact portion 50 (see FIG. 10 which is a cross-sectional view taken along the line Bxe2x80x94B of FIG. 9).
The resilient contact piece portion 52 is electrically connected at its contact portions 52a and 52b to a terminal of a mating connector.
Thus, the resilient contact piece portion 52 is supported only by the relatively-narrow interconnecting portion 51 extending from the side wall of the box-shaped portion, and therefore there is achieved an advantage that the amount of fine sliding movement of the contact portions 52a and 52b relative to the terminal of the mating connector is small.
With the above construction, although the intended effect can be obtained for vibrations in lateral and vertical (upward and downward) directions, a vibration-absorbing effect of the interconnecting portion 51 is not effective for vibrations in a forward-rearward direction a (see FIG. 9). Therefore, the whole of the resilient contact piece portion 52 is turned about the interconnecting portion 51 to vibrate as shown in FIG. 10 (which is a cross-sectional view taken along the line Bxe2x80x94B of FIG. 9). Because of this construction, the vibration-absorbing effect is incomplete, and the above problem with respect to the fine sliding movement has not yet been solved.
This invention seeks to solve the above problem. More specifically, an object of the invention is to provide an electrical contact which can be formed by one member, and even when vibrations develop in a forward-backward direction (terminal-inserting direction), a trouble, such as the increase of an electric resistance due to a fine sliding movement, will not occur.
The above object has been achieved by an electrical contact of claim 1 including a tubular portion, and a contact piece portion which is provided within the tubular portion so as to contact a contact portion of a mating connector terminal, inserted into the tubular portion through one open end thereof, to be electrically connected to the contact portion; provided in that the contact piece portion is supported by a contact piece portion-interconnecting portion, extending from an edge of the other open end of the tubular portion, in such a manner that the contact piece portion is held out of contact with an inner surface of the tubular portion.